5
IRIS DIAPHRAGM
– a multi-leaf round shaped device which is controlled
by a lever. It is similar to a camera shutter, and is installed under the
condenser. By moving the lever back and forth, the iris diaphragm opens
and closes, increasing and decreasing the contrast of the specimen. If the
image is “washed out” the iris diaphragm is opened too wide. If the image
is too dark the iris is not open wide enough.
NOSEPIECE
– the
revolving turret that holds the objective lenses,
permitting changes in magnification by rotating different powered
objective lenses into the optical path. The nosepiece must “click” into
place for the objectives to be in proper alignment.
OBJECTIVES
– the optical systems which magnify the primary image of
the instrument. Magnifications are typically 4X, 10X, 40X and 100X.
PHASE CONTRAST
– The phase contrast microscope reveals fine detail
in transparent objects which possess very little contrast. Unstained living
organisms and cells can be studied without destroying the specimen or
changing its composition by using fixing and staining reagents. Before
the advent of phase contrast such specimens could only be examined in
transmitted light by closing down the substage condenser diaphragm to a
small aperture. The narrow cone of illumination produced diffraction with
destruction of detail.
SIEDENTOPF
–
a binocular head design where the interpupillary
adjustment (increasing or decreasing the distance between the
eyepieces) is achieved by twisting the eyepiece tubes in an up and down
arc motion similar to binoculars.
STAGE
– the table of the microscope where the slide is placed for
viewing. This component moves upward and downward when the
focusing knobs are turned. The stage of the M10D has a built-in
mechanical stage with a below-
stage ergonomic “X” and “Y” axis controls.
A finger clip holds the slide securely and is designed to be a slow return
holder to provide protection to the specimen.
IMPORTANT TERMINOLOGY
“COATED” LENS
– in attempting to transmit light through glass, much of
the light is lost through reflection. Coating a lens increases the light
transmission by reducing or eliminating reflection, thus allowing more light
to pass through.
COMPOUND MICROSCOPE
– a microscope having a primary magnifier
(the objective) and a second (the eyepiece) to both conduct light, amplify
